It originally bonded with Spider-Man, but after its evil motives influenced Peter Parker, he rejected it. The symbiote has merged with many hosts, but the most well known is Eddie Brock.
From the time bonded with Spider-Man, it absorbed his abilities that can be emulated by its host. Venom is undetectable to Spider-Man's spider-sense ability but is vulnerable to loud noises. Venom is one of Spider-Man's greatest enemies and has a great hatred of its past host.